The pair were fierce Championship rivals in 2010 and 2012, with Vettel and Red Bull ultimately triumphing on both occasions.
Alonso returned to Formula 1 this year with Alpine after a two-year hiatus, and Vettel has said he is already enjoying sharing a track with the Spaniard once again.
“I like racing against him,” Vettel told Spanish sports newspaper Marca.
“In the first race this year, when Fernando came back, we had a wheel-to-wheel fight and I was smiling in the cockpit because I’m looking forward to more this year and I think we’ve had a few already. I think I always enjoyed fighting with Fernando.”
Vettel also revealed that he was impressed by Alonso’s talent even before he made it to F1 – and he was especially impressed when he accomplished the seemingly impossible task of beating Michael Schumacher.
“During the race at the Hungaroring in 2003 I was sitting in front of the TV and I remember watching him. I think his talent is unquestionable, his skills on the track are some of the greatest the sport has ever seen.
“Alonso did something I thought was impossible to do, namely beat Schumacher. When I was growing up Michael was the best, the number one, and it seemed impossible to beat him. Fernando started beating him, so I think it was a great achievement.
“And of course, he’s had a long career and in many different cars, so I consider it a pleasure to race alongside him and compete against him on the track,” the German added.